A known blower unit used in heating, ventilation and air conditioning (HVAC) applications includes subcomponents such as an electric motor, a blower wheel (sometimes referred to in the art as a "squirrel-cage" fan), and a housing. The electric motor, in one well known configuration, includes a stator including a stator core and windings, and a rotor including a cylindrical shaped magnetic rotor core and a rotor shaft concentric with the rotor core. The rotor core is located in, and rotatable relative to, the stator bore. The rotor shaft is coupled at one end to the blower wheel. Each subcomponent, e.g., the motor, the blower wheel, and the housing, of the above described blower assembly is separately manufactured. The separately manufactured subcomponents are then assembled to form the blower unit.
In operation, the stator windings are energized and generate a rotating magnetic field. The rotating magnetic field generated by the stator windings couples with the magnetic field of the magnetic rotor core. The rotor begins to rotate when the magnetic fields couple, and the blower wheel rotates with the rotor shaft.
The blower unit cost typically is one of the highest cost components in an HVAC system. Therefore, any reduction in the cost of the blower unit may be significant with respect to economic feasibility of an HVAC system. Since the blower unit subcomponents are manufactured separately, in the past, blower unit costs typically have been reduced by reducing the cost of the separate subcomponents. Of course, reducing the cost of a subcomponent typically results in reducing the cost of the overall unit.
In addition to the blower unit cost, the efficiency of a blower unit also is important, particularly in an HVAC application. For example, in an HVAC system, the blower unit may operate for extended periods of time year round. The efficiency of the blower unit, therefore, is important to maintain energy consumption at a reasonable level.
It would be desirable to provide a lower cost, in terms of both material costs and labor costs, blower unit than known blower units. Such a lower cost blower unit, however, should not be any less efficient to operate than the known blower units.